Tissue and organ regeneration research has focused on the need to stimulate regeneration by activating stem cells by soluble factors or treat partially- or non-functional cells to improve their function, e.g. by breaking damage-related crosslinks. Such research has overlooked the need to remove inhibitory effects.
Aging results from a combination of factors, but regeneration can overcome aging effects, if and to the extent that regenerative stem cells are functional. The stem cells, which replace cells, re-grow structures and renew the tissues of the body after normal wear-and-tear, give rise to replacement cells, and even structures, like hair follicles. In fact, if all stem cells in the body were destroyed, death would follow in a matter of days.
However, in a variety of diseases, malfunctions (such as male pattern baldness) and tissue injuries, cell types are not observed to be replaced when damaged or nonfunctional. Stem cell transplant therapy is proposed for such conditions, although it is not always successful.
The art has been left with the question as to why, then, does the body succumb to injury and aging when it has a mechanism for regeneration.